Introduction

• John Muir

  • Scottish naturalist

  • Advocate for preserving natural areas.

  • The John Muir trail travels along the Sierra Nevada.

• Because of geologists, we have learned how our planet formed and the processes that formed it.

What is Geology and Why Do We Study It?

Slide 4: Locations

• Crystal Cave, Mexico

  • Gypsum crystals, unusual large size.

  • Formed deep underground with hot hydrothermal waters flowing through void.

• Floating Mountains, China

  • Formed in karst environment.

  • Limestone was weathered away by water to create spikes.

• Fly Geyser, Nevada

  • Created on accident, farmers tried to dig a well.

  • Hydrothermal waters were beneath the surface.

  • Precipitates out of calcium carbonate cones.

  • Cones continue to build up.

• Rainbow Mountain, Peru

  • Vibrant colors from interactions with minerals in different types of sediments interacting with oxygen.

• Blood Falls, Antartica

  • Saline waters mix with fresh water melting from glaciers.

  • Natural water glacier.

  • Water is iron-rich, so it oxidizes at the surface (looks like blood).

Slide 5: Why Geology is Important

• Can help up prepare for natural disasters.

• Geologists can locate fault lines.

  • Geologists inform city planners, engineers, and insurance companies where fault lines are in order to plan better for natural disasters.

  • Earthquakes, tsunamis, volcanic activity, landslides, etc.

Resources

• Geologists provide the science behind the economic impact of drilling or mining resources that come from our planet.

• Examples: Minerals, fossil fuels (oil, gas, coal).

Slide 8: The Earth Over Time

• The Earth has not always had the same appearance.

• Continents were connected at one point, then broke apart.

  • Supercontinent Pangea

• They shifted over time.

• Land submerged from under the ocean.

• Fossils were separated from original continents and moved with other land.

• 100 million years ago is when the Earth began to get its recognizable appearance.

Slide 10: Important Information About Earth

• Geological age

  • Studying layers of rock.

  • Order of events.

• Internal structure

  • The Earth’s layers.

  • Discovered that Earth has internal structure.

• Plate tectonics

  • Learning what parts of the planet are moving

  • Plate tectonics are the driving force for the rock cycle.

    • Rocks form and transform through a cycle.

Formation of the Universe

Slide 13: The Big Bang

• The Big Bang Theory proposes that all matter and energy in the Universe started out as a single infinitesimally small point.

• It exploded and has been expanding since.

• The first few seconds after the explosion the smallest amount of energy started to form subatomic particles.

• In the first minute after the Big Bang, the subatomic particles joined to form the first element, Hydrogen.

• Within the first five minutes, we basically have all of the matter in the world in the form of hydrogen and helium.

• Galaxy is thought to be 95 billion light years across.

• Galaxy continues to expand.

Slide 15: The First Stars

• Hydrogen and Helium formed our first stars.

• The first star is formed a few hundred million years after the Big Bang.

• Nebula:

  • Concentrated amounts of hydrogen and helium that start to take on a gravitational attraction and pull materials towards it (collecting more hydrogen and helium).

  • More material makes it become hotter and hotter until it gets to the point where it ignites and is a mass of fusion.

  • Increased heat makes hydrogen and helium turn into heavier elements.

  • Hydrogen fusion

Slide 18: The Death of a Star

• Stars have a finite amount of hydrogen.

• Hydrogen is their main fuel.

• When it runs out of hydrogen, it gets dark.

• When supermassive stars die, they explode in a supernova.

Slide 19: Formation of the Elements

• Big Bang nucleosynthesis formed the lightest elements.

  • Hydrogen and Helium.

• Stella nucleosynthesis led to fusion of elements during the life cycle of a star.

  • Up to Iron (Fe)

• Elements with atomic numbers larger than 26 formed during supernovae nucleosynthesis (atomic number 27 to 92).

Building the Solar System

• Cosmic dust - a mass of hydrogen, helium, and other elements.

• Cosmic dust and gas begin clinging together due to electrical charges that act on them.

• They build a mass and collect more debris, forming a planet.

• When that happens, the mass causes the hole of the nebulous cloud to start rotating around and flatten out.

Slide 24: Our Solar System

• 99.98% of all of the material that was once in the nebulous cloud is now held within the sun.

• A blast sent out lighter elements and pushed them to farther parts of the solar system.

• The heavier elements, refractory elements, came together to make up rocky bodies.

Slide 25: Distance From the Sun Visual

• The frost line, also known as the snow line or ice line, is the distance from the central protostar of a solar nebula where the temperature is low enough for volatile compounds to condense into solid grains.

Slide 28: Differentiation of the Earth’s Interior

• When our planet began forming, denser material started to sink to our core.

• Differentiation is the organization of the Earth into layers.

• Led to the formation of a core, a crust, and eventually continents.

• The light elements were driven from the interior to form an ocean and atmosphere.

• Denser elements = core

• Lighter elements = surface

• Differentiation created the magnetosphere, atmosphere, and our tectonic plates.

Slide 34: Earth’s Magnetosphere

• Our magnetosphere is an invisible flow that is a magnetic field that surrounds our planet.

• Can send magnetic fields our far away from our planet and is generated from the interior part of the Earth (from core).

• Generated from the core separated into two layers:

  • Outer core - liquid (metal)

  • Inner core - solid

• When the liquid metal core starts to flow around solid metal, our inner core generates the electric current and sends the magnetic field lines out and away from our planet.

• Because solar wind is forcing itself towards our planet, they cause an elliptical form of out magnetic field lines.

• The magnetosphere protects us from solar winds, gamma ray, and x-ray (pushes these harmful energies away from us).

• Allows visible light to come into our planet.

Slide 35: Auroras

• The magnetosphere creates Auroras

  • Some material, like charged particles getting released from the sun, enters the magnetic lines where there’s weakness at the north and south poles. When it enters, it tangles with the poles, interacts with nitrogen and oxygen in our atmosphere and create vibrant colors.

• Other planets have auroras because they have refractory cores.

Class Question

• Do you think any of the other planets have auroras?

  • Yes, they have refractory cores that send out magnetic field lines which interact with solar winds, creating auroral lights on all the planets.

Class Question

• When the Earth had JUST formed, which gases do you think made up its atmosphere?

  • Hydrogen and helium

Slide 43: Earth’s Atmosphere

• Our atmosphere has different pressures.

• Blue oxygen and nitrogen haze

  • Visible light interacts with blue wavelengths and interacts with the gases in our atmosphere (N and O), then it scatters, resulting in the blue haze.

• Allows us to breathe.

Slide 45: The Geosphere

• On Earth’s sphere, there is a great dynamic surface with lots of topography across the globe.

  • Deep oceans

  • High mountains

• Plate tectonics are responsible for high amount of rain and ocean trenches.

Slide 49: Earth’s Interior

• Using sound waves, we can know what the interior of the Earth looks like.

• The interior is divided up in layers:

  • Crust - made out of lighter minerals

  • Upper mantle

  • Transition zone

  • Lower mantle

  • Outer core - liquid

  • Inner core - solid

• By volume, the most of our planet exists in the mantle.

• The lithosphere and asthenosphere are tectonic layers.

• Lithosphere - the crust and upper mantle, both act rigid.

• Asthenosphere - the soft layer in the lower part of the mantle.

• Our tectonic plates are comprised of the lithosphere.

• Below the tectonic plates is the asthenosphere.

• Tectonic plates are moving and recycling material and hydrating out the lighter materials.

Extra Notes

• Geological studies can put the achievements and consequences of human civilization in a larger context.

• The term “Earth System” is used to describe the set of processes operating on Earth because there are many related physical processes on Earth.

  • There are many processes operating on Earth that are complexly interrelated, yielding a system that is neither systematic, predictable, nor constant.

• The Big Bang began with all matter and energy concentrated into a singularity, an infinitesimally small point. The Big Bang occurred more than 13 billion (not million) years ago; at the instant of explosion, temperatures were too hot for atoms to form. The Big Bang theory is the explanation for how our Universe (not our Solar System) began.

• Atoms that are heavier than iron are generally produced by high-energy fusion reactions during the explosion of supernovae.

  • Very heavy elements form during supernovae explosions. Once ejected into space, atoms from stars and supernovae explosions form new nebulae or mix back into existing nebulae.

• The formation of the universe: Initially, all matter and energy was condensed into a single point, called a singularity. For reasons still unknown, the singularity exploded and sent matter and energy racing outwards. Slowly, the pieces of matter moved towards each other due to minute gravitational forces and eventually formed stars. The gravitational attraction between stars caused them to clump together into galaxies. Eventually, a supernova explosion of an ancient star began the formation of our Solar System, in which the Earth formed. After billions of years of evolution, humans evolved and became the dominant species on the planet.

  • First, all matter is condensed into a single point.

  • Then, the singularity explodes.

  • After, the first stars began to form, followed by the formation of the galaxies.

  • Finally, humans evolved.

• The Solar System started as a cloud of dust and gases called a nebula. The matter in the nebula flattened into a spinning disk.  At the center of the spinning disk, materials became so hot that atoms started to fuse together, a process that created the Sun. Surrounding the Sun, dust and gas particles collided to form planetesimals that then collided with other planetesimals to form larger bodies with strong gravitational fields. The gravity of each large body, or planet, forced it into a spherical shape and smoothed out the surface.

• Gravitational force was responsible for causing particles in the protoplanetary disk to clump and bind together, growing from soot-sized specks into boulder-sized blocks, and eventually into planetesimals.

• The magnetic field deflects most of the solar wind, so most of the particles in the wind do not reach Earth's surface. The magnetic field acts like a shield against the solar wind. If strong particles do make it through the magnetic shield into the magnetosphere, they are trapped in the Van Allen radiation belts.

  The Van Allen belts are areas composed of solar-wind particles and cosmic rays

• A dipole is a magnetic field that has a north pole and a south pole

• The heliosphere is a region of space far beyond the Earth's orbit in which the few atoms present come from the solar wind.

• The aurorae are formed by the interaction of the solar wind with the Earth's magnetic field lines at the poles.

• Through differentiation, the Earth’s interior separated into layers according to density.

• Layers of the Earth (from outer layers to inner layers):

  • Crust (lowest density)

  • Upper mantle

  • Lower mantle

  • Outer core

  • Inner core (highest density)

• The crust is the thinnest level and is broken up into two sections.

  • Continental and oceanic

• The rate at which temperature increases as depth increases is the geothermal gradient.

• Iron, Oxygen, Silicon, and Magnesium make up most of the mass of the whole Earth.